Electronic communication and siren systems are well known, perhaps the most prevalent use being in law enforcement vehicles. The officer must have the ability to alert the general public of his presence during high speed maneuvers and this is commonly performed by sounding a loud siren over a public address speaker amounted on the vehicle. It is also necessary for the officer to be able to communicate via a radio system with the control dispatcher or other officers. The common system in use involves a hand-held microphone. When the officer wishes to transmit over the radio, he keys it by depressing a switch on the microphone, thus activating the microphone and allowing transmission. When he finishes his transmission, he unkeys the microphone, thereby allowing the radio to receive incoming transmissions.
It is almost always necessary for the officer to transmit over the radio during high speed pursuits or maneuvers, for example to relay his position or request assistance. It is also absolutely necessary that the loud siren be in operation as much as possible to alert pedestrians and other vehicles of his approach. This creates a serious problem with regard to communications, in that the officer's voice is often drowned out by the siren. This creates the need to have information repeated or risk the possibility of miscommunication.